Have you had the chance to take any training? The basic CAF/MWS training covers some foundation concepts like Skin Development. Additionally, there is some documentation on the Administering_My_webMethods_Server.pdf that covers using the Skin Editor.
Additionally, in 8.2 you can create an MWS Skin Project in Designer where you can edit the skin directly in Designer.
Regards,
–mark
#webMethods#MWS-CAF-Task-Engine#webMethods-BPMS